The harmful effects of the lethal radiation would only surface days after the exposure, prosecutors said.

The alleged plot was broken up the Albany FBI Joint Terrorism Task Force, which includes personnel from federal and local authorities.

“This investigation revealed unthinkable plotting and planning of terrorist activity that targeted unsuspecting innocent citizens,” said New York State Police Superintendent Joseph D’Amico.

“This case demonstrates how we must remain vigilant to detect and stop potential terrorists, who so often harbor hatred toward people they deem undesirable,” said U.S. Attorney Richard Hartunian.

The device Crawford and Feight designed and intended to use was never operable, prosecutors said.

“It is the obligation of the FBI and our law enforcement partners to protect the public when individuals create plans to commit violent acts such as those charged today,” said Special Agent in Charge Andrew Vale.

The two face up to 15 years in prison and a $250,000 fine if convicted.